"If you take into account the health benefits of reduced pollution and the avoidance of climate impacts such as extreme weather and coastal damage, then the effect on GDP is even lower," he says.

"The cost of letting climate change happen is a lot more than the cost of mitigation."

Pearman says this latest IPCC report, the third in a series, underpins similar findings from Australian and international research, including the Stern report.

"They all come to the same conclusion that it's not that expensive to mitigate climate change, especially if we start early and we share the future amongst different energy sources."

These include nuclear, solar and wind power, the report says.

Other recommended greenhouse gas reduction strategies include more energy-efficient buildings and lighting, as well as capturing and storing carbon dioxide from coal-fired power stations, and oil and gas rigs.

"Cutting emissions not only protects us from dangerous climate change, but also provides other important benefits that typically are not counted in economic studies. These include better public health, greater energy security and the benefits of innovation," he says.

"Another key message is that improving energy efficiency, especially in buildings, provides an enormous opportunity globally for cutting emissions at low cost, and in some cases actually saves money."

"Although substantial uncertainties remain, the IPCC report concludes that 'even for the most stringent of stabilisation pathways assessed' the costs of reducing carbon emissions are comparable to or lower than the economic damage avoided," he says.

"In other words, the economic benefits of deep cuts in emissions outweigh the costs."

Too costly

But a US environmental official rejects some options detailed in the report for cutting emissions as too costly.

"There are measures that come currently at an extremely high cost because of the lack of available technology," says James Connaughton, head of the White House Council on Environmental Quality.

These scenarios, he says, would bring cuts in world GDP up to 3%. "That would of course cause global recession, so that is something that we probably want to avoid," he says.